Semiconductor compounds

ABSTRACT

This invention comprises a semiconducting polymer having a permittivity greater than 3.4 at 1000 Hz and a charge mobility in the pure state greater than 10 −7  cm 2 V −1 s −1  and more preferably greater than 10 −6  cm 2 V −1 s −1 . Preferred polymers include repeating units of triarylamines which have specific cyano and/or alkoxy substitution. They are suitable for use in electronic components such as organic thin film transistors.

This invention relates to novel semiconducting polytriarylaminepolymers.

Polyarylamine and polytriarylamine compounds have been known for manyyears and have useful properties causing them to be used in electronicdevices. Among their useful properties is that these compounds aresemiconductors.

In recent years research into polyarylamines has centred aroundproducing compounds having improved charge mobility. A considerable bodyof prior art exists relating to polyarylamine polymers. The mostrelevant prior art is Application number WO 1999/32537 which isprimarily concerned with photoelectric effects and use of thesecompounds in the field of electrophotography. This specification reviewsa large body of earlier work related to polyarylamines and as itsinventive step proposes a method of making polyarylamines using endcapping agents to control the molecular weight of said compounds. Thecompounds of the present invention may or may not be end capped.(WO199/32537) claims among other things a range of substituentsincluding nitrilo, nitro, cyano and C₁-C₄ alkoxy substitution and“carbyl derived” substituents which from the text on page 21 would seemto cover a very wide range of compounds. Both polymers and copolymersare covered (see page 20). The inventors of patent application(WO199/32537) have not referred to or recognised any significancerelating to the dielectric constant of the compounds and have notdisclosed how an increase in permittivity could be achieved.

Subsequent workers in the field of organic electronics have usedpolyarylamines in combination with non-polymeric organic semiconductorsbut have specifically rejected binders which have permittivity above 3.3at 1000 Hz (see WO02/45184 and WO 2005/055248). In WO 2007/078993further attempts to use binders of permittivity greater than 3.3produced very poor charge mobilities which are a critical aspect of theperformance of semiconductors formulations used in organic field effecttransistors.

We have discovered a novel class of polytriarylamines which haveincreased permittivity which is believed to alter their polarity andsurface properties and increase their attractiveness for use assemiconducting binders used in combination with non-polymericsemiconductors.

Co-pending PCT and Taiwanese patent applications entitled “Transistorsand Methods of Making Them” of common filing date and filed by TheCentre For Process Innovation Ltd provide further information relatingto this. The co-pending application and the present application sharecommon priority dates of 26 May 2011 and 1 Nov. 2011, the applicationnumbers of the priority documents of the co-pending application in theUnited Kingdom being respectively 1108865.5 and 1118868.7.

This invention comprises a semiconducting polymer represented by Formula(I) having a permittivity greater than 3.4 preferably at least 3.5 andsuitably at least 3.7, for example at least 4.1 at 1000 Hz and a chargemobility in the pure state of greater than 10⁻⁷ cm²V⁻¹ s⁻¹ morepreferably greater than 10⁻⁶ cm²V⁻¹s⁻¹ for example greater than 10⁻⁵cm²V⁻¹s⁻¹. In general the higher the charge mobility the better.

Preferred polymers are those of Formula (I) which can be homopolymers orcopolymers. Copolymers are those polymers prepared from two or moredifferent monomers and include terpolymers, tetrapolymers and the like.The monomers can join to form random, block, or segmented copolymers, aswell as any variety of other structural arrangements.

The invention comprises a polytriarylamine polymer of Formula (I)wherein:

-   R^(x) is independently hydrogen, an alkyl group preferably having 1    to 10 carbon atoms, an alkoxy group preferably having 1 to 10 carbon    atoms, halogen, a nitro group or R^(y); where each R^(y) is    independently a cyano group (CN), or an organic group that includes    at least one CN group, with the proviso that at least one repeat    unit and preferably at least 30 percent of the repeat units in the    triarylamine polymer includes an R^(y) group and that the sum of    indices (j+k+l) is at least one. Sufficient groups R^(y) should be    present in the polymer to ensure that its permittivity is greater    than 3.4 at 1000 Hz. It will be appreciated that the R^(x) groups    may not be the same in all of the repeat units of the first part of    Formula 1.-   R^(Z) is independently in each occurrence an alkyl group and is    intended to include not only pure open chain saturated hydrocarbon    alkyl substituents such as methyl, ethyl, propyl, t-butyl and the    like, but also alkyl substituents bearing further substituents known    in the art, such as hydroxyl, alkoxy, alkylsulphonyl, halogen atoms,    cyano, nitro, amino, carboxyl, etc. Thus “alkyl group” includes    ether groups, haloalkyls, etc. Preferred R^(Z) groups include C₁-C₂₀    hydrocarbyl groups, and more preferably C₁-C₅ alkyl groups, more    preferably methyl groups,

Different selections from the alternatives within the definitions ofR^(x) and R^(y) may be made in different units of the polymer.

A is independently in each occurrence hydrogen, halogen or any suitableend-capping group including those described in WO 1999/32537,

-   j and l are independently in each occurrence 0 to 4,-   k is independently in each occurrence 0 to 5, more preferably the    sum of indices (j+k+l), which may differ between different monomer    units is at least 1 in at least 10% of the monomer units.-   a is the number of monomer units of Formula (II) in the    polytriarylamine compound, if it is a homopolymer then the polymer    will have 100% of monomer of Formula (II). The copolymers preferably    comprise between 5-100% of monomer of Formula (II), more preferably    10-80% of monomer of Formula (II), still more preferably 30-70% of    monomer of Formula (II),-   b is the number of monomer units of monomer of Formula (III) in the    polytriarylamine compound, in some cases b will equal 0,-   X is a halogen, for example Br or I but more preferably Cl.-   * (asterisk)—represents halogen atoms or a suitable leaving group

As used herein, the term “organic group” means a carbon atom, ahydrocarbon group (with optional elements other than carbon andhydrogen, such as cyano, oxygen, nitrogen, sulphur, silicon andhalogens) that is classified as an aliphatic group, cyclic group, orcombination of aliphatic and cyclic groups (e.g. alkaryl and aralkylgroups). The term aliphatic group means a saturated or unsaturatedlinear or branched hydrocarbon group. This term is used to encompassalkyl, alkenyl, and alkynyl groups for example. The term “alkyl” groupmeans a saturated linear or branched hydrocarbon group including forexample, methyl, ethyl, isopropyl, t-butyl, hexyl, heptyl, 2-ethylhexyland the like. The term “alkenyl group” means an unsaturated linear orbranched hydrocarbon group with one or more carbon-carbon double bonds,such as a vinyl group. The term “alkynyl group” means an unsaturatedlinear or branched hydrocarbon group with one or more carbon-carbontriple bonds. The term “cyclic group” means a closed ring hydrocarbongroup that is classified as an alicyclic, aromatic, or heterocyclicgroup. The term “alicyclic group” means a cyclic hydrocarbon havingproperties resembling those of aliphatic groups. The term “aromaticgroup” or aryl group means a mono- or polynuclear aromatic hydrocarbongroup, including within its scope alkaryl or aralkyl groups. The term“heterocyclic group” means a closed ring hydrocarbon in which one ormore of the atoms in the ring is an element other than carbon (e.g.nitrogen, oxygen, sulphur, etc.).

The number average molecular weight of the polymers is suitably in therange 1000 to 500,00 for example 5000 to 100,000.

For certain embodiments, the semiconducting polymer includes a groupthat can be cross-linked and on cross-linking and patterning therebyrenders the semiconducting layer less susceptible to dissolution whenlayers are solution coated on top of it.

The polytriarylamine copolymers thus comprise repeat units of Formulae(II) and (III) of which at least some are substituted by cyano groups orby groups which comprise cyano groups or alkoxy groups.

The polymer preferably has cyano substitution on any of the aromaticrings in the polytriarylamine units: more preferably if cyano groups aredirectly substituted onto the aromatic ring they should be in the 2and/or 6 positions relative to the nitrogen atom. It is preferred thatsuch cyano substitution is on the “pendant” aromatic ring, that is, thearomatic ring which is not directly bonded into the polymer ‘backbone’chain. It is also preferred that the cyano group should be attachedindirectly through a linking group.

In another preferred case the polymer preferably has alkoxy substituentsdirectly substituted onto the aromatic ring. These substituents shouldbe in the 2, 4, and/or 6 positions relative to the nitrogen atom. It ismore preferred that such alkoxy substitution is on the “pendant”aromatic ring. If a cyano group is also present it is preferred that thecyano group is in the 2-position on the pendant aromatic ring.

In a most preferred case, R^(X) is a group having a linker group betweenthe pendant aromatic ring and a cyano group. The linker group may be analkyl group, a substituted alkyl group (for example —CH₂CN, —CR₂—CN)which is substituted with at least one additional cyano group. Thelinker group may be a phenylene group which may be substituted forexample by an additional CN group; suitably R^(x) may be a group offormula —C₆H₄CN, —C₆H₄—CH₂CN or —C₆H₄—(CR₂)CN.

A preferred repeat unit is represented by Formula (IIa)

in which the group or groups D are independently CN groups or groupswhich comprise a CN group attached to the aromatic ring by a linkinggroup, and/or D are alkoxy groups.

In one embodiment, of the invention, polymers of Formula (I) have one ortwo of the R^(X) groups preferably as a cyano group, preferably in the2,4 and/or 6 positions on the pendant aromatic ring. Most preferably onecyano group is located on the 2-position on the pendant aromatic ring(see Example 1).

In another preferred case R^(X) is a methoxy group on the pendantaromatic ring in polymers of Formula (I), in this case k ispreferably >1 and more preferably the methoxy groups are substituted onthe 2 and 4-positions on the pendant aromatic ring (see Example 2).

If a cyano group is also present it is preferred that the cyano group isin the 2-position.

PREPARATIVE EXAMPLES 1 TO 9 AND COMPARATIVE EXAMPLES 10 TO 15

NMR data was collected using instruments supplied by JEOL, specificallymodels ECX 300 and ECX 400.

All solvents used were of HPLC grade, unless otherwise stated.

Silica gel purifications were carried out using Davisil® 60 Å 40-63 μm,a product of Grace Davison Discovery Sciences, unless otherwise stated.

The number average molecular weight (Mn) quoted in the Examples hereinwere determined by gel permeation chromatography using a Hewlett Packard1100 HPLC system with UV detection @ 254 nm, liquid chromatography datawas processed using a CIRRUS GPC-Multi detector software calibratedagainst polystyrene standards (supplied by Varian 13 points molecularweight range 162-113300).

Also for convenience the Examples herein which are polymers areidentified by the substituents on the aromatic rings in the repeat unit(for example 2-cyano-polytriarylamine polymer). Examples 1 to 8 andComparative Example 10 to 15 were all synthesised by polymerising thecorresponding dihalo substituted monomer(s), no end-capping reagent asdefined in WO 1999/32537 was used in this invention. Example 9 wassynthesised using Suzuki polymerisation. The polymerisation methoddescribed in WO 1999/32537 is equally applicable to preparing thepolymers of this invention.

Method for the Measurement of the Permittivity, ∈_(r) of the Polymers

The permittivities of the semiconducting polymers in Examples 1 to 9 andin the Comparative Examples 10 to 15 were measured by fabricatingcapacitors according to the method detailed below.

50 nm titanium bottom contact pads were prepared using sputter coatingand standard photolithography and wet etching techniques. Thesemiconducting polymer of interest was then coated from solution, usinga spin coater, to obtain a film thickness of typically greater than 500nm. The solvents used to dissolve the materials are shown in the textbelow. A top contact pad of approximately 50 nm aluminium was thendeposited using shadow mask evaporation. The capacitance was measuredusing a calibrated Agilent Precision LCR meter E4980A set at a frequencyof 1000 Hz. Film thickness measurements were performed using a Dektaksurface profilometer and cross correlated with a Taylor Hobson TalysurfCCl white light interferometer. The two techniques were found to agreeto within +/−3% for all films studied. The area of overlap for the topand bottom contact pads, i.e. the area of the capacitor formed, wasmeasured using a Zeiss stereo microscope equipped with image analysissoftware. Using these values the permittivities were then calculatedusing the equation:

$\begin{matrix}{ɛ_{r} = \frac{C \cdot d}{A \cdot ɛ_{0}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

-   Equation 1: Calculation of permittivity.-   Where,-   ∈_(r) is the permittivity of the polytriarylamine analogue-   C is the measured capacitance of the capacitor-   d is the thickness of the film of the polytriarylamine analogue-   A is the area of the capacitor and ∈_(o) is the permittivity of free    space (a constant with a value of 8.854×10⁻¹² F/m).

The capacitor array used contains 64 capacitors with areas of 0.11 cm²and 0.06 cm² respectively (32 of each size). The standard deviation forthe value of permittivity on each array was calculated, which includesthe standard deviation of capacitance, film thickness and areameasurement combined. In addition, where possible, each semiconductingpolymer was tested at two different film thicknesses to confirm that thepermittivity value did not vary with film thickness.

Permittivity Data

Using the above described method the data included in Table 1 wasobtained.

TABLE 1 Details of capacitor arrays fabricated and measured for eachpolymer Average Film Permittivity, Polymer Thickness, ε_(r)(Polytriarylamine = PTAA) nm (s.d, %) 2-Cyano-PTAA homopolymer 767^(c)3.88 (2.2) Example (1) 736^(c) 3.64 (2.3) 758^(c) 3.97 (3.2)2,4-DiMeO-PTAA homopolymer 2195^(d)  4.09 (3.9) Example (2) 659^(c) 3.77(0.9) 645^(c) 3.70 (2.3) 404^(q) 3.84 (0.8) 4-isopropylcyano-PTAAhomopolymer 998^(e) 5.80 (2.3) Example (3) 936^(e) 6.04 (1.1) 481^(f)5.86 (3.9) 50:50 random copolymer of 4-isopropylcyano 706^(a) 4.05 (5.1)PTAA: 2,4-dimethyl-PTAA 466^(b) 4.07 (2.6) Example (4) 467^(b) 4.05(1.0) 30:70 random copolymer of 4-isopropylcyano 606^(o) 3.73 (2.1)PTAA: 2,4-dimethyl-PTAA 604^(o) 3.66 (0.4) Example (5) 453^(p) 3.63(1.3) 2,4-Dimethoxyphenyl-PTAA homopolymer 897^(r) 3.47 (2.2) Example(6) 893^(r) 3.55 (0.7) 574^(s) 3.50 (1.8) 573^(s) 3.52 (1.8) 50:50copolymer of 4-isopropylcyanophenyl- 1057^(r)   4.13 (0.96) PTAA:2,4-Dimethyl-PTAA 966^(r)  3.92 (1.56) Example (7) 535^(s)  3.88 (2.08)546^(s)  4.22 (4.16) 4-cyclohexylcyano-PTAA homopolymer 520^(u)  4.12(12.8) Example (8) 293^(v)  4.0 (18.9) 282^(v)  4.10 (11.4) 70:302,4-Dimethyl-PTAA: 4-isopropylcyano- 460^(o)  3.52 (0.98) PTAA Bis-arylend terminated copolymer 458^(o)  3.55 (4.13) Example (9) 368^(p)  3.66(6.52) 367^(p)  3.69 (2.97) 2,4-Dimethyl-PTAA homopolymer 10641^(g,h) 3.08 (8.3) Comparative Example (10) 9307^(g,h)   3.00 (12.8)12510^(h,i)  2.99 (9.3) 3-Methoxy-PTAA homopolymer 12547^(i,j)   3.29(10.5) Comparative Example (11) 9575^(i,j)  3.29 (8.4) 2,4-Difluoro-PTAAhomopolymer   883^(k,l) 3.22 (2.6) Comparative Example (12)   846^(k,l)3.32 (3.8)   614^(g,l) 3.24 (2.9) 3,5-bis(trifluoromethyl)-PTAAhomopolymer   730^(k,m)  2.80 (2.12) Comparative Example (13)  756^(k,m) 2.84 (3.5) Backbone-2-Methoxy-PTAA homopolymer 453^(o)  3.30(2.32) Comparative Example (14) 436^(o)  3.28 (2.67) 365^(y)  3.26(0.75) 378^(y)  3.33 (1.50) 4-Phenoxy-PTAA homopolymer 826^(w) 2.90(4.9) Comparative Example (15) 435^(x) 2.59 (3.8) ^(a)5 wt % of polymerformulated in tetralin, coated at 300 rpm, 20 s ^(b)5 wt % of polymerformulated in tetralin, coated at 500 rpm, 20 s ^(c)5 wt % of polymerformulated in o-dichlorobenzene, coated at 300 rpm, 20 s ^(d)10 wt % ofpolymer formulated in o-dichlorobenzene, coated at 300 rpm, 20 s ^(e)3wt % of polymer formulated in dichloromethane, coated at 300 rpm, 20 s^(f)2 wt % of polymer formulated in dichloromethane, coated at 300 rpm,20 s ^(g)Prepared using gold top and bottom contacts and capacitors withan area of 0.24 cm² ^(h)10 wt % of polymer formulated in toluene, coatedat 700 rpm, 20 s ^(i)Prepared using gold top and bottom contacts andcapacitors with an area of 0.15 cm² ^(j)10 wt % of polymer formulated intetralin, coated at 500 rpm, 20 s ^(k)Prepared using gold top and bottomcontacts and capacitors with an area of 0.11 and 0.06 cm² ^(l)10 wt % ofpolymer formulated in toluene, coated at 500 rpm, 20 s ^(m)5 wt % ofpolymer formulated in 50/50 vol THF/cyclohexanone, coated at 300 rpm, 20s ^(o)5 wt % of polymer formulated in toluene, coated at 300 rpm, 20 s^(p)5 wt % of polymer formulated in toluene, coated at 500 rpm, 20 s^(q)5 wt % of polymer formulated in o-dichlorobenzene, coated at 500rpm, 20 s ^(r)5 wt % of polymer formulated in bromobenzene, coated at300 rpm, 20 s ^(s)5 wt % of polymer formulated in bromobenzene, coatedat 500 rpm, 20 s ^(u)3 wt % of polymer formulated in phenetole, coatedat 100 rpm, 20 s ^(v)3 wt % of polymer formulated in phenetole, coatedat 200 rpm, 20 s ^(w)7 wt % of polymer formulated in tetralin, coated at300 rpm, 20 s ^(x)7 wt % of polymer formulated in tetralin, coated at500 rpm, 20 s ^(y)5 wt % of polymer formulated in toluene, coated at 400rpm, 20 s

The mobillities of the polymers were measured via fabrication of OTFTson glass as described below.

Method for Fabricating the Organic Thin Film Transistors (OTFTs) and forCharacterising Mobility, (μ) in cm²/Vs

OTFTs were fabricated in top gate configuration (refer to FIG. 1) usingglass substrates. The method of fabrication is as described below.

Glass Based OTFT Devices

4″ square glass substrates (ex Corning Eagle 2000) were cleaned usingsonication 20 minutes in Deconex (3% in water) followed by rinsing inultrapure water and dried using compressed air. The source and drainmetal (Au 50 nm on top of Ti 5 nm) was sputter coated onto the glass.The source-drain (SD) electrodes were patterned using standardphotolithography and wet chemical etching. The transistor SD pattern onthe lithographic mask consisted of electrodes with channel lengthsranging from 4 μm, 10 μm, 30 μm, and 100 μm, and channel widths of 0.5mm, 3 mm and 15 mm. The pattern was arrayed to produce 36 transistors ofeach channel length over a 4″ square substrate. Following inspection ofthe etched pattern, the photoresist material was stripped chemically andthe SD channel lengths were measured using a compound microscope. Thesubstrates then underwent plasma treatment (model PE100, ex Plasma EtchInc.) using 50 sccm argon/50 sccm oxygen plasma and a RF power of 250 W,treatment time 60 s. Prior to spin coating of the OSC solution, a 10 mMsolution of pentafluorobenzenethiol was applied to the surface of theelectrodes for 1 minute followed by spin coating and rinsing in2-propanol, followed by drying on a hotplate at 100° C. The organicsemiconductor (OSC) formulation was spin coated onto the SD electrodesusing a Suss RC12 spinner set at 1000 rpm followed by baking on ahotplate for 60 seconds at 100° C. A solution of 2 parts Cytop CTL 809M(Asahi Glass) to 1 part FC43 solvent (Acros Organics) was spin coated at1500 rpm and the sample was baked on a hotplate for 60 s at 100° C. Gateelectrodes were defined by evaporation of gold through a shadow mask ina thermal evaporator system.

OTFT Characterisation

OTFTs were tested using a Wentworth Pegasus 300S semi-automated probestation in conjunction with a Keithley S4200 semiconductor parameteranalyser. This allowed a statistically significant number of OTFT devicemeasurements to be made on each substrate. The Keithley systemcalculated the linear mobility according to the equation shown below(Equation 2)

$\mu = {\frac{\partial I_{DS}}{\partial V_{G}}\frac{L}{{WC}_{i}V_{DS}}}$

Where L is the transistor length, W is the transistor width and C_(i) isthe dielectric capacitance per unit area. V_(ds) was set at −2V unlessotherwise stated. The mobility values reported are an average of the 5highest points in accumulation for each transistor. The standarddeviation of the mobility values is reported as a percentage of themean, and the number of devices measured is indicated in the table ofresults also.

TABLE 2 TFT mobility of each polymer, with polymer formulation detailsNumber of Mobility at working 4 μm transistors channel Standard testedon Polymer length, deviation of substrate (Polytriarylamine = PTAA)Polymer formulation cm²/Vs mobility, % (out of 36) 2-cyano-PTAAhomopolymer 1 wt % in 1.2 × 10⁻⁶ 6.6 27 Example (1) bromobenzene2,4-DiMeO-PTAA 1 wt % in   3 × 10⁻⁴ 11.7 12 homopolymer bromobenzeneExample (2) 4-isopropylcyano-PTAA 1 wt % in 1.1 × 10⁻⁶ 2.7 3 homopolymerdichloromethane Example (3) 50:50 random copolymer, 4- 1 wt % intetralin   8 × 10⁻⁵ 15.4 25 isopropylcyano PTAA: 2,4- dimethyl-PTAAExample (4) 30:70 random copolymer, 4- 1 wt % in toluene   1 × 10⁻⁴ 14.735 isopropylcyano-PTAA: 2,4- dimethyl-PTAA Example (5)2,4-Dimethoxyphenyl-PTAA 1 wt % in   5 × 10⁻⁴ 5.5 19 homopolymerbromobenzene Example (6) 50:50 copolymer of 1 wt % in   1 × 10⁻⁴ 6.0 294-isopropylcyano phenyl- bromobenzene PTAA: 2,4-Dimethyl-PTAA Example(7) 4-cyclohexylcyano-PTAA 1 wt % in phenetole   1 × 10⁻⁵ 9.5 13homopolymer Example (8) 70:30 2,4-Dimethyl-PTAA: 1 wt % in toluene 1.7 ×10⁻⁴ 24.9 32 4-isopropylcyano-PTAA Bis- aryl end terminated copolymerfrom Suzuki coupling, Example (9) 2,4-Dimethyl-PTAA 1 wt % in toluene3.7 × 10⁻³ 12.7 27 homopolymer Comparative Example (10) 3-Methoxy-PTAA 1wt % in tetralin 8.4 × 10⁻⁴ 5.4 17 homopolymer Comparative Example (11)2,4-Difluoro-PTAA 1 wt % in tetralin 9.2 × 10⁻⁵ 29.8 25 homopolymerComparative Example (12) 3,5-bis(trifluoromethyl)-PTAA 1 wt % in 9.3 ×10⁻⁶ 26.8 18 homopolymer THF/Cyclohexanone Comparative Example (13) (1:3by volume) Backbone 2-methoxy PTAA 1 wt % in toluene 6.8 × 10⁻⁵ 4.0 27homopolymer Comparative example (14) 4-Phenoxy-PTAA 1 wt % in tetralin1.1 × 10⁻³ 6.6 32 homopolymer Comparative Example (15)

Preparative Examples 1 to 9 Example (1) Synthesis of the 2-cyano-PTAAPolymer (1)

1(a) Synthesis of the 2-cyano monomer

A 500 milliliter (mL) 3-neck round bottom flask fitted with magneticstirrer, thermometer, condenser and argon inlet was charged with 250 mLN-methylpyrrolidinone (GPR grade, Sigma Aldrich) which was then degassedfor 15 minutes. 24.2 grams (g) of 2-fluorobenzonitrile (Fluorochem),23.8 g of bis(4-chlorophenyl)amine (Example 3) and 30.4 g of caesiumfluoride (Alfa-Aesar) were added to the vessel and was heated to 175° C.for 18 hours, before cooling to room temperature. The mixture was pouredinto water (1800 mL), extracting with toluene. The organic phase wasdried (magnesium sulphate)(MgSO₄) and concentrated to give a brownsolid. This material was slurried in methanol to give a tan solid, whichwas further purified by recrystallising from methanol and charcoal togive the product as a tan solid. Yield: 21 g. ¹H NMR (400 MHz, CDCl₃): δ7.6 (1H, m, ArH), 7.5 (1H, m, ArH), 7.3-7.15 (6H, m, ArH), 6.9 (4H, m,ArH)

Synthesis of the 2-cyano-PTAA homopolymer

A 500 ml three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. 200 mL of anhydrousN,N-dimethylacetamide (Sigma Aldrich) was charged to the vessel viacannula needle and was degassed with argon for 15 minutes.Triphenylphosphine (7.78 g, Sigma Aldrich), 2,2′-bipyridyl (368miligrams (mg), Sigma Aldrich), zinc (11.38 g, Alfa Aesar) and nickel(II) chloride (253 mg, Sigma Aldrich) were added to the vessel. Thecontents were heated to 70-80° C. where the mixture turned red-brown incolour. A few crystals of iodine were added, and the reaction was leftto stir for 1 hour. The monomer (19.95 g) was added to the vessel.Anhydrous toluene (29 mL, Sigma Aldrich) was added, and the reaction wasleft to stir at 70-80° C. for 19 hours, before being cooled to roomtemperature. The reaction was filtered through celite, eluting withN,N-dimethylacetamide (50 mL). The filtrates were added dropwise to astirred portion of methanol (1.5 liters (L)). The suspension was stirredfor 1 hour, collected by vacuum filtration and washed with methanol. Thefilter cake was dissolved in dichloromethane (500 mL) and washed with 1Maqueous sodium hydroxide solution (250 mL), three times with water(3×250 mL), dried (sodium sulphate) (NaSO₄) and concentrated to give anorange solid. A solution of this material was prepared by dissolving theproduct in 120 mL of tetrahydrofuran at 50° C. and diluting with 60 mLof toluene. This solution was filtered through silica gel, eluting with2:1 mixture of tetrahydrofuran: toluene (800 mL). The combined filtrateswere concentrated to give a yellow solid. The material was dissolved intetrahydrofuran (180 mL) and charged to a 500 mL round bottom flaskequipped with magnetic stirrer and condenser. Activated charcoal (1.8 g)was added and the mixture was heated to 60° C. for 35 minutes. Themixture was filtered through filter paper in a Buchner funnel, washingwith tetrahydrofuran. The carbon screening was repeated three times intotal, filtering the third treatment through a glass sinter funnel. Thefiltrates were concentrated to give a yellow-orange solid. A solution ofthis material was prepared in tetrahydrofuran (100 mL) and addeddropwise to a stirred portion of methanol (400 mL). The suspension wasstirred for 1 hour, collected by vacuum filtration, washed with methanoland dried to constant weight to give the product as a yellow solid. Thisprecipitation was then repeated, using 120 mL of LC tetrahydrofuran and400 mL of methanol, to give the product as a yellow powder. Yield: 12.72g. Mn=2514 g/mol. n=9.4. Polydispersity=2.0.

The dielectric constant of polymer (1) was 3.8.

Example (2) Synthesis of the 2,4-dimethoxy-PTAA polymer (2)

2(a): Synthesis of the 2,4-dimethoxy-PTAA monomer

A 2 liter (L) 3-neck round bottom flask fitted with magnetic stirrer,thermometer, argon inlet and condenser was charged with 875 mL oftoluene, which was degassed for 15 minutes. 5.12 g of palladium (II)acetate (Precious Metals Online) and 13.19 g of4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (Alfa-Aesar) werecharged to the vessel. The mixture was heated to 50° C. with stirring,and once the internal temperature reached 50° C., was cooled to roomtemperature. The mixture was left to stir at room temperature for 1hour. 2,4-dimethoxyaniline (35 g, Alfa-Aesar), 4-chloroiodobenzene(119.70 g, Apollo Scientific) and sodium-tert-butoxide (48.25 g,Alfa-Aesar) were added and the reaction was heated to 95° C. for 18hours. The reaction was cooled to room temperature and filtered througha silica pad. The filtrates were concentrated to give a brown solid.This material was recrystallised from isopropyl alcohol/acetone. Aftercooling, the solids were collected by vacuum filtration and washed threetimes with cold isopropyl alcohol/acetone. The solids wererecrystallised further from dichloromethane/methanol to give the productas a brown solid. Yield: 30.95 g. ¹H NMR (300 MHz, CDCl₃): δ 7.1 (4H, m,ArH), 6.8 (4H, m, ArH) 3.8 (3H, s, ArOMe), 3.6 (3H, s, ArOMe).

Synthesis of the 2,4-dimethoxy-PTAA polymer (2)

A 500 mLI three neck round bottom flask was fitted with overheadstirrer, thermometer, air condenser, Claisen adaptor and septum inlet.The apparatus was flushed with argon. 150 mL of anhydrousN,N-dimethylacetamide (Sigma Aldrich) was charged to the vessel viacannula needle and was degassed with argon for 15 minutes.Triphenylphosphine (5.36 g, Sigma Aldrich), 2,2′-bipyridyl (250 mg,Sigma Aldrich), zinc (8.1 g, Alfa-Aesar) and nickel (II) chloride (150mg, Sigma Aldrich) were added to the vessel and the contents were heatedto 70-80° C. The solution turned red-brown and a few crystals of iodinewere added to the mixture. The reaction was left to stir for 1 hour atthis temperature before the monomer (15 g) and anhydrous toluene (24 mL,Sigma Aldrich) was added. The reaction was left to stir at 70-80° C. for19 hours. The reaction was cooled to room temperature and filteredthrough a celite pad, eluting with N,N-dimethylacetamide. The filtratewas added dropwise into a stirred portion of methanol (1250 mL). Thesuspension was stirred for 1 hour, before being collected by vacuumfiltration. The solids were dissolved in dichloromethane (250 mL) andwashed with 1M aqueous hydrochloric acid (200 mL), water (2×200 mL),dried (sodium sulphate) and concentrated to give an orange-yellow solid.This was dissolved in tetrahydrofuran (200 mL) and filtered throughsilica gel, eluting with tetrahydrofuran. The filtrates were combinedand concentrated to give an orange solid. The material was dissolved intetrahydrofuran (250 mL) and charged to a 500 mL round bottom flaskfitted with magnetic stirrer and condenser. Activated charcoal (1.14 g)was added and the mixture was heated to 60° C. for 30 minutes. Themixture was filtered through filter paper in a Buchner funnel and washedwith tetrahydrofuran. The carbon screening was repeated three times intotal, filtering the third treatment through a glass sinter funnel. Thefiltrates were concentrated to give an orange-yellow solid. A solutionof this material in tetrahydrofuran (64 mL) was added dropwise to astirred portion of methanol (320 mL). The suspension was stirred for 45minutes, before being collected by vacuum filtration, washed withmethanol, and dried. This precipitation procedure was repeated a secondtime using tetrahydrofuran (95 mL) and methanol (475 mL) to give ayellow solid. This solid was then stirred in methanol (350 mL) for 2hours and filtered. A final precipitation using tetrahydrofuran (60 ml)and methanol (300 mL) gave, after drying, the product as a yellow solid.Yield: 6.3 g. Mn=3471 g/mol. n=11.5. Polydispersity=2.6.

The dielectric constant of polymer (2) was 3.9

Example 3 Synthesis of the 4-isopropylcyano polytriarylamine homopolymer(3)

3(a): Synthesis of intermediate compound, 4-Iodophenylacetonitrile

A round bottomed flask fitted with a magnetic stirrer was charged with1.22 g of copper iodide (Sigma Aldrich), 25 g of4-bromophenylacetonitrile (Apollo Scientific) and 38.37 g of sodiumiodide (Sigma Aldrich) under argon. The round bottomed flask wasevacuated and backfilled with argon three times.N,N′-Dimethylethylenediamine (1.38 mL, Sigma Aldrich) and 25 mL dioxanewere added and the mixture was heated to 110° C. for 2 hours (h). Thereaction was allowed to cool to room temperature (rt) and 125 mL of 30%aqueous ammonia was added. The mixture was then poured onto 500 mL waterand extracted three times with dichloromethane (DCM) and the combinedorganics dried over MgSO₄. The solvent was removed under reducedpressure to afford the title compound as brown oil that solidified onstanding. Yield: 29.97 g. ¹H NMR (400 MHz, CDCl₃), δ 7.71 (2H, d, Ar—H),7.08 (2H, d, Ar—H), 3.66 (2H, s, CH₂).

3(b): Synthesis of the intermediate compound2-(4-iodophenyl)-2-methylpropanenitrile

A three necked round bottom flask, fitted with a thermometer, argoninlet and stirrer bar, was charged with 15.82 g sodium tert-butoxide(Alfa-Aesar) in 25 mL tetrahydrofuran (THF, Univar) under argon andcooled to 0° C. N-Methylpyrrolidinone (NMP) (25 mL) was then added. Asolution of 10 g of 4-iodophenylacetonitrile and 10.2 mL methyl iodide(Sigma Aldrich) in 22 mL THF:NMP (1:1, volume: volume (v/v)) wasprepared and this was added to the cooled reaction mixture at such arate as to keep the temperature below 10° C. On completion of theaddition, the reaction was allowed to warm to rt and stirred for 2 h. 3Maqueous hydrochloric acid (HCl) (120 mL) was added followed by 120 mLtoluene, the phases were separated and the aqueous layer extracted twomore times with 120 mL toluene. The combined organic layers were washedwith saturated aqueous sodium bicarbonate (120 mL), brine (120 mL),aqueous sodium thiosulfate solution (120 mL) and dried over MgSO₄.Removal of the solvent under reduced pressure gave the crude product asa brown oil. Purification by column chromatography in ethylacetate/heptane mixtures gave the title compound as a pale yellow oil.Yield: 4.55 g. ¹H NMR (400 MHz, CDCl₃), δ 7.71 (2H, d, Ar—H), 7.23 (2H,d, Ar—H), 1.70 (6H, s, CH₃).

3(c): Synthesis of intermediate compound Bis(4-chlorophenyl)amine

A 10 L jacketed vessel fitted with overhead stirrer, temperature probe,argon inlet and condenser was charged with 6.6 L of anhydrous toluene(Sigma Aldrich) and then degassed for 15 minutes. 7.46 g of palladium(II) acetate (Precious Metals Online) and 20.64 g of racemic2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (Alfa-Aesar) were added tothe vessel, and the contents were heated to 50° C. with stirring, beforebeing cooled back to room temperature once internal temperature reached50° C., and left to stir for an hour. 4-chloroaniline (443.98 g,Alfa-Aesar), 4-chloroiodobenzene (794.49 g, Apollo Scientific) andsodium-tert-butoxide (318.63 g, Alfa-Aesar) were charged to the vesseland the contents were heated to reflux for 2 hours, whereupon HPLCanalysis showed no remaining starting materials. The reaction was cooledto room temperature and washed with water (3.3 L), 2M aqueoushydrochloric acid (3.3 L), water (3.3 L) and brine (3.3 L). The organicphase was dried (sodium sulphate) and concentrated to give a brownsolid. This was recrystallised in 6:1 methanol:water (total volume of6.53 L) to give the product as a light brown solid. Yield: 362 g. ¹H NMR(400 MHz, CDCl₃): δ 7.22-7.20 (4H, m, ArH), 6.96-6.94 (4H, m, ArH), 5.62(1H, s, Ar₂NH)

3(d): Synthesis of2-(4-(bis(4-chlorophenyl)amino)phenyl)-2-methylpropanenitrile; alsocalled the 4-isopropylcyano-PTAA monomer

Palladium acetate (261 mg, Precious Metals Online) and (+/−)2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (723 mg, Alfa-Aesar) wereadded to 400 mL of degassed toluene which was then heated under argon to45° C. over 30 minutes. The solution was cooled and2-(4-iodophenyl)-2-methylpropanenitrile (28.6 g),bis-(4-chlorophenyl)amine (25.12 g) and sodium tert-butoxide (11.15 g)were added over ten minutes. On completion of addition, the reactionmixture was heated to reflux for 20 h. The reaction mixture was cooled,filtered through a silica plug and solvent removed under reducedpressure. Purification by column chromatography using EtOAc/heptanemixtures gave the product as a yellow solid. The product was thenrefluxed in methanol (150 mL) and filtered hot to give a cream solid.The solids from the filtrate were also collected and the combined solidsrecrystallised from 57 mL industrial methylated spirits (IMS): EtOAc(1:2, v/v), filtered and washed with IMS (30 mL) to give a cream solid.Yield: 10.5 g. ¹H NMR (400 MHz, CDCl₃) δ 7.31 (2H, d, Ar—H), 7.21 (4H,d, Ar—H), 6.97-7.02 (6H, m, Ar—H), 1.71 (6H, s, 2×CH₃).

Synthesis of the 4-isopropylcyano-PTAA homopolymer (3)

A 500 ml three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. 150 mL of anhydrousN,N-dimethylacetamide (Sigma Aldrich) was charged to the vessel viacannula needle and was degassed with argon for 15 minutes.Triphenylphosphine (3.53 g, Sigma Aldrich), 2,2′-bipyridyl (169 mg,Sigma Aldrich), zinc (5.37 g, Alfa-Aesar) and nickel (II) chloride (99mg, Sigma Aldrich) were added to the vessel and the contents were heatedto 70-80° C. The solution turned red-brown and a few crystals of iodinewere added to the mixture. The reaction was left to stir for 1 hour atthis temperature before the monomer (10.8 g) and anhydrous toluene (18mL, Sigma Aldrich) were added. The reaction was left to stir at 70-80°C. for 18 hours. The reaction was cooled to room temperature, causingthe mixture to slowly gel. Once at room temperature, the mixture fullygelled. This was filtered, and the collected solid was dissolved indichloromethane (500 mL) and filtered through celite, eluting withdichloromethane (2×500 mL). The filtrates were concentrated to give adamp residue, which was triturated in methanol (500 mL) and filtered togive a yellow solid. This solid was dissolved in dichloromethane (500mL) with sonication and washed with 1M aqueous sodium hydroxide solution(250 mL) and water (3×250 mL), before drying (sodium sulphate) andconcentrating to give a yellow solid. A solution of this material wasprepared in dichloromethane (100 mL), requiring extended sonication, andfiltered through a silica pad, eluting with dichloromethane. Thefiltrates were concentrated to give a yellow solid. This was dissolvedin dichloromethane (50 mL), requiring extended sonication, and addedslowly to a stirred portion of methanol (250 mL). The suspension wasstirred for 2 hours, before being filtered, washed with the filtrate andmethanol and dried to constant weight to give product as a yellow solid.Yield: 3.11 g.

The dielectric constant of polymer (3) was 5.9.

Example 4 Polymer (4), 50:50 4-isopropylcyano-PTAA: 2,4-dimethyl-PTAAcopolymer

Synthesis of the 2,4-dimethyl PTAA monomer

A 10 L jacketed vessel fitted with overhead stirrer, temperature probe,argon inlet and condenser was charged with 4.5 L of toluene, which wasdegassed for 15 minutes. 5.56 g of palladium (II) acetate (PreciousMetals Online) and 15.47 g of racemic2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (Alfa-Aesar) were charged tothe vessel. The mixture was heated to 50° C. with stirring, and once theinternal temperature reached 50° C., was cooled to room temperature. Themixture was left to stir at room temperature for 1 hour.2,4-Dimethylaniline (300.03 g, Alfa-Aesar), 4-chloroiodobenzene (1306.51g, Apollo Scientific) and sodium-tert-butoxide (523.87 g, Alfa-Aesar)were added and the reaction was heated at reflux for 24 hours, whereuponHPLC analysis showed complete reaction. The reaction was cooled to roomtemperature and washed twice with water (2×4 L) and the organic phasewas filtered through celite, giving a second split, which was separated.The organics were then concentrated to give a brown solid (935.5 g).838.46 g of this material was recrystallised from 3:1 industrialmethylated spirits (IMS): ethyl acetate (4450 mL) in a 6 L jacketedvessel fitted with overhead stirrer, temperature probe, argon inlet andcondenser. The suspension was cooled to 0° C. for 1 hour, then thesolids collected by vacuum filtration and washed three times with cold3:1 IMS:ethyl acetate (3×840 mL). The solids were dried overnight togive the product as a grey solid. Yield: 699 g. ¹H NMR (300 MHz, CDCl₃):δ 7.16-6.86 (11H, m, ArH), 2.35 (3H, s, ArMe), 1.99 (3H, s, ArMe).

Synthesis of the 50:50 2,4-dimethyl: 4-isopropylcyano PTAA copolymer (4)

A 500 mL three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. 200 mL of anhydrousN,N-dimethylacetamide (Sigma Aldrich) was charged to the vessel viacannula needle, and degassed with argon for 15 minutes.Triphenylphosphine (6.5 g, Sigma Aldrich), 2,2′-bipyridyl (0.29 g, SigmaAldrich), zinc (9.52 g, Alfa-Aesar) and nickel (II) chloride (0.19 g,Sigma Aldrich) were added to the vessel. The contents were heated to70-80° C. A few crystals of iodine were added to facilitate catalystformation, turning the solution red-brown. The mixture was stirred atthis temperature for a further hour. The 2,4-dimethyl monomer (8.12 g)and the 4-isopropylcyano monomer (9 g) were added to the vessel,followed by anhydrous toluene (27.5 mL, Sigma Aldrich). The reaction wasstirred at 70-80° C. for 20 hours, before being cooled to roomtemperature. The solids were collected by vacuum filtration andredissolved in toluene at 50° C. The mixture was cooled and the excesszinc was removed by filtration. The filtrates were washed with 1Maqueous sodium hydroxide solution (250 mL), water (250 mL) and 10%aqueous sodium chloride solution (250 mL), before being dried (sodiumsulphate) and concentrated to give a yellow solid. This material wasdissolved in toluene (100 mL) and filtered through silica, eluting withtoluene. The filtrates were concentrated to give a yellow solid. Thematerial was dissolved in toluene (250 mL) and charged to a 500 mL roundbottom flask fitted with magnetic stirrer and condenser. Activatedcharcoal (0.4 g) was added and the mixture heated to 50° C. for 30minutes. The mixture was filtered through filter paper in a Buchnerfunnel and washed with toluene. The carbon screening was repeated threetimes in total, filtering the third treatment through a glass sinterfunnel. The filtrates were concentrated to give a yellow solid. Asolution of this material was prepared in tetrahydrofuran (80 mL), whichwas added dropwise to a stirred portion of methanol (400 mL). Theresulting suspension was stirred for 1 hour, before being collected byvacuum filtration, washing with methanol, and drying to a constantweight, to yield the product as a yellow powder.

Yield: 2.6 g. Mn=15091 g/mol. n=26. Polydispersity=1.18.

The dielectric constant of polymer (4) was 4.1.

Example (5) Polymer (5) 30:70 4-isopropylcyano-PTAA: 2,4-Dimethyl PTAAcopolymer

5(a): Synthesis of 4-Iodophenylacetonitrile

A mixture of potassium cyanide (33.23 g, Sigma-Aldrich) and 4-iodobenzylbromide (101 g, Apollo Scientific) in 3:1 IMS/water (1 L) was heated toreflux for 2 hours then cooled to room temperature. The organics wereremoved in vacuo and the aqueous was extracted with EtOAc (2×750 mL).The combined organics were washed with brine (300 mL), dried (magnesiumsulphate) and concentrated in vacuo to give the product as oil thatsolidified on standing. Yield: 78.4 g. ¹H NMR (400 MHz, CDCl₃): δ 7.71(2H, d, ArH), 7.08 (2H, d, ArH) 3.66 (2H, s, ArCH₂CN).

5(b): Synthesis of 2-(4-Iodophenyl)-2-methylpropanenitrile

NMP (197 mL, Sigma-Aldrich) was added to a suspension of sodiumtert-butoxide (124.0 g, Alfa-Aesar) in THF (197 mL, Univar) under argon.The mixture was cooled to 0° C. and a solution of iodomethane (87.9 mL,Sigma-Aldrich) and 4-iodophenylacetonitrile (78.4 g) in a 50:50 mixtureof NMP/THF (173 mL) was added dropwise keeping the internal temperaturebelow 10° C. The mixture was warmed to room temperature and stirredovernight. 2M HCl (930 mL) and toluene (930 mL) were added then theaqueous layer was separated and extracted with toluene (2×465 mL). Thecombined organics were washed with saturated sodium bicarbonate (930mL), brine (930 mL), 2M sodium thiosulfate (930 mL), dried (magnesiumsulphate) and concentrated in vacuo to a yellow/orange solid.Purification by column chromatography eluting with EtOAc/heptanemixtures gave the title compound as a pale yellow oil. Yield 4.55 g, ¹HNMR (400 MHz, CDCl₃): δ 7.71 (2H, d, Ar—H), 7.23 (2H, d, Ar—H), 1.70(6H, s, CH₃).

5(c):2-(4-(bis(4-chlorophenyl)amino)phenyl)-2-methylpropanenitrile:4-isopropyl-cyano-PTAAmonomer

Palladium acetate (261 mg, Precious Metals Online) and (±)2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) (723 mg, Alfa-Aesar)were added to 400 mL of degassed toluene which was then heated underargon to 45° C. over 30 minutes. The solution was cooled and2-(4-iodophenyl)-2-methylpropanenitrile (28.6 g),bis-(4-chlorophenyl)amine (25.12 g) and sodium tert-butoxide (11.15 g)(were added over ten minutes. On completion of addition, the reactionmixture was heated to reflux for 20 h. The reaction mixture was cooled,filtered through a silica plug and solvent removed under reducedpressure. Purification by column chromatography using EtOAc/heptanemixtures gave the product as a yellow solid. The product was thenrefluxed in methanol (150 mL) and filtered hot to give a cream solid.The solids from the filtrate were also collected and the combined solidsrecystallised from acetonitrile, washing the solids with acetonitrile(×2). Yield 10.5 g. ¹H NMR (400 MHz, CDCl₃) δ 7.31 (2H, d, Ar—H), 7.21(4H, d, Ar—H), 6.97-7.02 (6H, m, Ar—H), 1.71 (6H, s, 2×CH₃).

Synthesis of 30:70 4-isopropylcyano-PTAA: 2,4-Dimethyl PTAA copolymer

A 500 mL three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (278.5 mL, SigmaAldrich) was charged and degassed for 15 minutes. Triphenylphosphine(10.74 g, Aldrich), 2,2′-bipyridyl (500 mg, Sigma Aldrich), zinc (15.85g, Alfa-Aesar) and nickel (II) chloride (300 mg, Aldrich) were added tothe vessel. The contents were heated to 70-80° C. where the mixtureturned red-brown in colour. A few crystals of iodine were added, and thereaction was left to stir for 1 hour. The 2,4-dimethyl (18.87 g) and4-isopropylcyano (8.99 g) monomers were added to the vessel. Anhydroustoluene (45 mL, Sigma Aldrich) was added. The reaction was left to stirat 70-80° C. for 19 hours, before being cooled to room temperature. Thereaction was filtered, washing the solids with N,N-dimethylacetamide.The filter cake was dissolved in toluene (500 mL) and filtered throughcelite. The filtrates were washed with 1M sodium hydroxide solution (250mL), water (250 mL) and 10% NaCl solution (250 mL), dried (sodiumsulphate) and concentrated to give a yellow solid. This material wasdissolved into toluene (250 mL) and filtered through silica, elutingwith toluene. The silica was also flushed with tetrahydrofuran to removeall product from the pad. Product fractions were combined andconcentrated to give a yellow solid (14.5 g). This was dissolved intoluene (500 mL) and charcoal treated. The filtrates were thenconcentrated to give a yellow solid. This material was dissolved intetrahydrofuran (80 mL) and added dropwise to methanol (400 mL) withstirring. After stirring for 1 hour, the resulting suspension wascollected by filtration to give a pale yellow powder. Yield: 9.9 g.Mn=9694 g/mol. n=34. Polydispersity=1.9.

The dielectric constant of polymer (5) was 3.7

Example 6 Polymer (6), 2,4-Dimethoxyphenyl-PTAA homopolymer

Synthesis of the 2,4-dimethoxyphenyl monomer

Tetrakis(triphenylphosphine)palladium(0) (Pd(PPh₃)₄) (6.62 g, PeakdaleMolecular) was added to a mixture of4-bromo-N,N-bis(4-chlorophenyl)aniline (Example 7a (i))(75 g),2,4-dimethoxyboronic acid (38.2 g, Alfa-Aesar) and sodium carbonate(64.7 g) in tetrahydrofuran (1120 mL) and H₂O (750 mL) under argon andthe mixture was heated to reflux overnight. The organics were separated,the aqueous layer was extracted with ethyl acetate (×2) and the combinedorganics were dried and concentrated to a black solid. The solid wasadsorbed onto silica and columned eluting ethyl acetate/heptane mixturesto give a green/brown solid. Methanol was added and the mixture wasstirred for 20 minutes then filtered and washed with methanol (×2).Methanol was added, the mixture was heated to 40° C. and dichloromethanewas added portion wise until all solids had dissolved. The solution wasstirred for 10 minutes, cooled in an ice-bath for 1 h then the solidswere filtered, washed with 50:50 methanol/dichloromethane (×2) and driedto give the product as a light green/brown solid. Yield: 40.8 g. ¹H NMR(400 MHz, CDCl₃): δ 7.40 (2H, d, ArH), 7.19-7.25 (5H, m, ArH), 7.00-7.05(6H, m, ArH), 6.55 (2H, m, ArH), 3.84 (3H, s, OMe), 3.81 (3H, s, OMe).

Synthesis of the 2,4-dimethoxyphenyl-PTAA polymer

A 500 mL three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (150 mL, SigmaAldrich) was charged and degassed for 15 minutes. Triphenylphosphine(4.54 g, Sigma Aldrich), 2,2′-bipyridyl (210 mg, Sigma-Aldrich), zinc(6.71 g, Alfa-Aesar) and nickel (II) chloride (130 mg, Sigma Aldrich)were added to the vessel and the contents were heated to 70-80° C. wherethe mixture turned red-brown in colour. A few crystals of iodine wereadded, and the reaction was left to stir for 1 hour. The monomer (15 g)was added to the vessel followed by anhydrous toluene (24 mL,Sigma-Aldrich). The reaction was left to stir for 15 hours before beingcooled to room temperature. The reaction was filtered, washing thesolids with N,N-dimethylacetamide. The filter cake was dissolved indichloromethane (500 mL) and filtered through celite. The filtrates werewashed with 1M hydrochloric acid (250 mL), water (250 mL) and 10% brinesolution (250 mL), dried (magnesium sulphate) and concentrated to give ayellow solid. This material was dissolved into dichloromethane (500 mL)and filtered through silica, eluting with dichloromethane. Productfractions were combined and concentrated to give a yellow solid. Thiswas dissolved in chloroform (250 mL) and charcoal treated. The filtrateswere then concentrated to give a yellow solid. This material wasdissolved in chloroform (150 mL) and added dropwise to a stirred portionof methanol (750 mL). The resulting suspension was stirred for 1 hourbefore being collected by filtration to give a pale yellow powder.Yield: 6.67 g. Mn=3368 g/mol.

n=8.8. Polydispersity=2.4.

The dielectric constant of polymer (6) was 3.5

Example 7 polymer (7), 50:50 4-Isopropylcyanophenyl-PTAA: 2,4-DimethylPTAA copolymer

7 (a): Synthesis of the 4-Isopropylcyanophenyl-PTAA monomer (i)4-bromo-N,N-bis(4-chlorophenyl) aniline

A 5 L three neck flat bottomed flask, fitted with a condenser,thermometer and argon inlet, was flushed with argon. The flask was thencharged with toluene (1.4 L), bis(4-chlorophenyl)amine, Compound ofExample 3(c), (40 g), 4-bromo iodobenzene (52.3 g, Apollo Scientific),tris(dibenzylideneacetone)dipalladium(0)Pd₂-(dba)₃) (461 mg, Acros),(±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (1.05 g, Alfa-Aesar) andsodium-tert-butoxide (35.5 g, Alfa-Aesar). The resulting black solutionwas heated to 100° C. for 48 hours then cooled and filtered through apad of celite, washing with toluene. The filtrate was concentrated toapproximately half volume before washing with water (1 L), saturatedbrine (14 drying over MgSO₄ and concentrating to a green oil.Purification by dry flash column chromatography eluting with ethylacetate/heptane mixtures followed by recrystallisation from acetonitrilegave the target compound. Yield: 32 g, off-white solid. ¹H NMR (400 MHz,CDCl₃): δ 7.35 (2H, m, Ar—H), 7.20 (4H, m, Ar—H), 6.98 (4H, m, Ar—H),6.92 (2H, m, Ar—H).

(ii) 4-(bis(4-chlorophenyl)amino)phenyl) boronic acid

A three neck round bottomed flask was fitted with a thermometer, argoninlet and a pressure equalizing dropping funnel. The flask was chargedwith anhydrous 2-methyltetrahydrofuran (1.1 L) and4-bromo-N,N-bis(4-chlorophenyl)aniline (60.9 g) before being cooled to−78° C. n-Butyllithium (1.95M solution in hexanes, 95.4 mL) was addeddropwise and the solution was stirred at −78° C. for 1 hour. Trimethylborate (26 mL, Sigma-Aldrich) was then added dropwise via syringe andthe reaction left to stir at −78° C. for 1.5 hours then warmed to roomtemperature overnight. 1M hydrochloric acid (630 mL) was addedportionwise to the reaction mixture, the layers were split and theorganics washed with water (600 mL), brine (600 mL), dried over MgSO₄and concentrated to a pale yellow solid. The solid was slurried inheptane and stirred at room temp. for 1 hour. The solid was filtered offand washed with heptane before being dried under vacuum to give a paleyellow powder. Yield: 39.3 g. ¹H NMR (400 MHz, CDCl₃): δ 8.02 (2H, m,Ar—H), 7.27 (4H, m, Ar—H), 7.05 (6H, m, Ar—H).

(iii)2-(4′-(bis(4-chlorophenyl)amino)-[1,1′-biphenyl]-4-yl)-2-methylpropanenitrile

A 2 L flat bottomed flask fitted with an argon inlet and condenser wascharged with (4-(bis(4-chlorophenyl)amino)phenyl)boronic acid (39.3 g),2-(4-odophenyl)-2-methylpropanenitrile, compound from Example 5 (c)(27.1 g) and tetrahydrofuran (591 mL). Sodium carbonate (33.9 g) wasdissolved in water (393 mL) and this was added to the tetrahydrofuranmixture. The reaction mixture was then heated to 75° C. for 16 hours.Ethyl acetate (200 mL) and water (200 mL) were added and the mixturefiltered through a celite pad. The layers were split, the organic layerswashed with brine (600 mL), dried over MgSO₄ and concentrated. Theresulting material was purified by flash column chromatography elutingwith ethyl acetate/heptane mixtures. The fractions were concentrated toa thick slurry and the solid filtered off, washed with heptane and driedunder vacuum to give an off-white solid. Yield: 27 g. ¹H NMR (400 MHz,CDCl₃): δ 7.56-7.42 (6H, m, Ar—H), 7.21 (4H, m, Ar—H), 7.15-7.02 (6H, m,Ar—H), 1.77 (6H, s, CH₃).

Isopropylcyanophenyl-PTAA:2,4-dimethyl-PTAA 50:50 copolymer

A 250 mL three-necked round bottom flask was fitted with overheadstirrer, thermometer, air condenser, Claisen adaptor and septum inlet.The apparatus was flushed with argon. N,N-dimethylacetamide (128 mL,Sigma Aldrich) was charged and degassed for 15 minutes.Triphenylphosphine (4.17 g, Sigma Aldrich), 2,2′-bipyridyl (191 mg,Sigma-Aldrich), zinc (6.16 g, Alfa-Aesar) and nickel (II) chloride (120mg, Sigma Aldrich) were added to the vessel. The contents were heated to70-80° C. where the mixture turned red-brown in colour. A few crystalsof iodine were added, and the reaction was left to stir for 1 hour. The2,4-dimethyl monomer (5.8 g) and2-(4′-(bis(4-chlorophenyl)amino)-[1,1′-biphenyl]-4-yl)-2-methylpropanenitrile(7.0 g) were added to the reaction followed by anhydrous toluene (21 mL,Sigma Aldrich) and the reaction was stirred at this temperature for 16hours. The reaction was cooled and the solids were filtered off, washingwith N,N-dimethylacetamide. Toluene (600 mL) was added and the mixturewas heated to 50° C. then filtered through a pad of celite. Theremaining solids were dissolved in dichloromethane (500 mL), warmed to40° C. then filtered through a pad of celite. The toluene filtrates wereconcentrated to a sticky solid, dichloromethane (500 mL) was added andcombined with the previous dichloromethane filtrates. The combinedorganics were washed with 1M aqueous sodium hydroxide (800 mL), water(800 mL), 10% brine (800 mL), dried over MgSO₄ and concentrated. Theresulting solid was dissolved in dichloromethane (250 mL) and passedthrough a silica pad, washing with dichloromethane. The combinedfractions were concentrated to a solid which was dissolved intetrahydrofuran (400 mL) and charcoal treated and concentrated to ayellow solid. The solid was dissolved in tetrahydrofuran (100 mL) andadded dropwise to methanol (500 mL), filtered and dried under vacuum togive the target compound. Yield: 4.85 g. Mn=7139 g/mol. n=10.8.Polydispersity=1.59.

The dielectric constant of polymer (7) was 4.0

Example 8 Polymer (8), 4-cyclohexylcyano-PTAA homopolymer

Synthesis of the 4-cyclohexylcyano PTAA oligomer1-(4-iodophenyl)cyclohexanecarbonitrile

N-Methylpyrrolidinone (NMP) (197 mL, Sigma-Aldrich) was added to asuspension of sodium tert-butoxide (124.0 g, Alfa-Aesar) intetrahydrofuran (THF) (197 mL, Univar) under argon. The mixture wascooled to 0° C. and a solution of 1,5-dibromopentane (87.9 mL,Sigma-Aldrich) and 4-iodophenylacetonitrile (78.4 g) in a 50:50 mixtureof NMP/THF (173 mL) was added dropwise keeping the internal temperaturebelow 10° C. The mixture was warmed to room temperature and stirredovernight. 2M hydrochloric acid (930 mL) and toluene (930 mL) were addedthen the aqueous layer was separated and extracted with toluene (2×465mL). The combined organics were washed with saturated sodium bicarbonate(930 mL), brine (930 mL), 2M sodium thiosulfate (930 mL), dried(magnesium sulphate) and concentrated in vacuo to a yellow/orange solid.Dichloromethane was added and the solid was filtered and washed withdichloromethane to give the product as a white solid. Yield: 22.55 g. ¹HNMR (400 MHz, CDCl₃): δ 7.70-7.72 (2H, m, ArH), 7.22-7.25 (2H, m, ArH),2.10-2.13 (2H, m, —CH₂—), 1.67-1.89 (7H, m, —CH—), 1.22-1.32 (1H, m,—CH—).

1-(4-(bis(4-chlorophenyl)amino)phenyl)cyclohexanecarbonitrile-4-cyclohexyl-cyanoPTAA monomer

A solution of palladium acetate (179 mg) and(±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (496 mg) in toluene (338mL) was heated to 50° C. then cooled to room temperature.1-(4-Iodophenyl)cyclohexanecarbonitrile (22.55 g),bis(4-chlorophenyl)amine (17.26 g) and sodium tert-butoxide (7.66 g)were added and the mixture was heated to reflux overnight. The mixturewas cooled to room temperature, filtered through a pad of silica thenconcentrated in vacuo to an oil. Purification by column chromatographyeluting ethyl acetate/heptane mixtures followed by recrystallisationfrom IPA gave the product as a white solid. Yield: 12.5 g. ¹H NMR (400MHz, CDCl₃): δ 7.31-7.35 (2H, m, ArH), 7.19-7.23 (4H, m, ArH), 6.97-7.04(4H, m, ArH), 2.14-2.17 (2H, m-CH₂—), 1.68-1.86 (7H, m, —CH₂—),1.20-1.32 (1H, m, —CH—).

Synthesis of 4-cyclohexylcyano PTAA oligomer

500 ml three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (125 mL,Sigma-Aldrich) was charged and degassed for 15 minutes.Triphenylphosphine (4.04 g, Sigma-Aldrich), 2,2′-bipyridyl (200 mg,Sigma-Aldrich), zinc (6.00 g, Alfa-Aesar) and nickel (II) chloride (120mg, Sigma-Aldrich) were added to the vessel and the contents were heatedto 70-80° C. where the mixture turned red-brown in colour. A fewcrystals of iodine were added and the reaction was left to stir for 1hour. The 4-cyclohexylcyano monomer (12.5 g) was added to the vesselfollowed by anhydrous toluene (20 mL, Sigma-Aldrich) and the reactionwas left to stir for 19 hours before being cooled to room temperature.The reaction was filtered, washing the solids withN,N-dimethylacetamide. The filter cake was dissolved in dichloromethane(250 mL) and filtered through celite. The filtrates were washed with 1Msodium hydroxide (250 mL), water (250 mL), 10% NaCl solution (250 mL),dried (sodium sulphate) and concentrated to give a yellow solid. Thismaterial was dissolved into dichloromethane (250 mL) and filteredthrough silica, eluting with dichloromethane. Product fractions werecombined and concentrated to give an off white solid (8 g). The solidwas dissolved in chloroform (250 mL) and charcoal treated three times(3×0.8 g charcoal). The filtrates were then concentrated to give an offwhite solid. This material was dissolved in chloroform (125 mL) andadded dropwise to a stirred portion of methanol (625 mL). The resultingsuspension was stirred for 1 hour before being collected by filtrationto give an off white powder. Yield: 6.5 g. Due to insolubility, no GPCdata was obtained.

The dielectric constant of polymer (8) was 4.1.

Example 9 polymer (9), 30:70 isopropylcyano-PTAA: 2,4-Dimethyl PTAABis-aryl end terminated copolymer

9(a): Synthesis of2-(4-(bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile (i)2-(4-(diphenylamino)phenyl)-2-methylpropanenitrile

Palladium(II) acetate (3.01 g, Precious Metals Online) and4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (7.76 g, ManchesterOrganics) were dissolved in toluene (550 mL) and the solution wasdegassed. Diphenylamine (22.7 g, Alfa-Aesar), sodium tert-butoxide (28.4g, Alfa-Aesar) and 2-(4-iodophenyl)-2-methylpropanenitrile (40 g) wereadded and the solution heated to 90° C. for 18 hours. The reaction wascooled, filtered through a celite pad, washed with water, brine, dried(MgSO₄) and concentrated. The residue purified by flash column elutingethyl acetate:heptane mixtures to give an oil. Heptane was added to theoil and the resulting solid was filtered to give the product as a whitesolid. Yield; 17.5 g. ¹H NMR (400 MHz, CDCl₃); 7.22-7.32 (9H, m),7.00-7.10 (6H, m), 1.71 (6H, s)

(ii) 2-(4-(bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile

2-(4-(diphenylamino)phenyl)-2-methylpropanenitrile (7.5 g) was dissolvedin ethyl acetate (128 mL). N-Bromosuccinimide (NBS) (8.55 g, ApolloScientific) was added portionwise before leaving the reaction to stir atroom temperature for 18 hours. The reaction mixture was washed withwater, sodium carbonate, brine, dried (MgSO₄) and concentrated. Heptanewas added to the residue and the resulting solid was filtered off togive the product as a grey solid. Yield; 6.4 g. ¹H NMR (400 MHz, CDCl₃);7.30 (6H, m), 7.04 (2H, d), 6.93 (4H, d), 1.71 (6H, s).

9(b): Synthesis of2-(4-(bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile (i)2,4-dimethyl-N,N-diphenylaniline

Toluene (735 mL) was degassed for 10 minutes then diphenylamine (15 g,Alfa Aesar), 4-iodoxylene 5 (21.6 g, Alfa-Aesar) and sodiumtert-butoxide (10.65 g, Alfa Aesar) were added before degassing for afurther 5 minutes. Pd₂(dba)₃ (812 mg, Acros) and tri-tert-butylphosphine(1.08 mL, Alfa Aesar) were added and the mixture was heated to 95° C.for 3.5 hours. The reaction was cooled, quenched with water (750 mL),stirred for 10 minutes then filtered through celite. The organic layerwas separated, washed with brine (2×500 mL), dried (MgSO₄) andconcentrated to a brown oil. Yield: 24.46 g. The oil was redissolved intoluene and passed through a silica plug. The filtrates wereconcentrated to give the title compound as a brown oil. ¹H NMR (400 MHz,CDCl₃): δ 7.16-7.23 (4H, m, ArH), 6.86-7.05 (9H, m, ArH), 2.33 (3H, s,CH₃), 2.00 (3H, s, CH₃).

(ii) N,N-Bis(4-bromophenyl)-2,4-dimethylaniline

NBS (31.55 g, Apollo Scientific) was added to a solution of2,4-dimethyl-N,N-diphenylaniline (24.23 g) in EtOAc (410 mL). Themixture slowly warmed over 5 minutes and was stirred for a further 1hour until the solution had re-cooled. The mixture was washed with water(250 mL), Na₂CO₃ (2×375 mL), brine (250 mL), dried (MgSO₄) andconcentrated to a dark brown solid. Recrystallisation from THF/MeCN gavethe title compound as a grey solid. Yield: 27.70 g. ¹H NMR (400 MHz,CDCl₃): δ 7.22-7.30 (4H, m, ArH), 7.05 (1H, d, ArH), 7.00 (1H, dd, ArH),6.95 (1H, d, ArH), 2.33 (3H, s, CH₃), 1.97 (3H, s, CH₃).

(c): Synthesis of2,4-Dimethyl-N,N-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline

A mixture of N,N-bis(4-bromophenyl)-2,4-dimethylaniline 7 (10 g),bis(pinacolato)diboron (12.96 g, Allychem), and potassium acetate (7.97g, Alfa-Aesar) in dioxane (250 mL) was degassed for 10 minutes then[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II) complexwith dichloromethane (947 mg, Peakdale Molecular) was added and themixture was heated to 100° C. overnight. The mixture was concentratedand the residue was dissolved in DCM (300 mL) and passed through a plugof celite. The filtrates were washed with water (2×200 mL), dried(MgSO₄) and concentrated to a dark brown solid.

Purification by column chromatography eluting with EtOAc/heptanemixtures followed by recrystallisation from THF/MeCN gave the titlecompound as a white solid. Yield: 5.60 g. ¹H NMR (400 MHz, CDCl₃): δ7.62-7.64 (4H, m, ArH), 6.92-7.05 (7H, m, ArH), 2.34 (3H, s, CH₃), 1.95(3H, s, CH₃), 1.29 (24H, s, CH₃).

Synthesis of 30:70 4-isopropylcyano-PTAA: 2,4-Dimethyl-PTAA copolymer 9a

2-(4-(Bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile (Example 9a(ii) (537.4 mg), N,N-bis(4-bromophenyl)-2,4-dimethylaniline (Example 9b(ii) (328.5 mg) and2,4-dimethyl-N,N-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline(Example 9 (c) (1.01 g) were added to a mixture of toluene:dioxane:water(9.3 mL:4.6 mL:4.6 mL) followed by potassium phosphate (1.61 g,Alfa-Aesar) and Aliquat 336 (4 drops, Alfa Aesar). The mixture wasdegassed for 10 minutes then Pd₂(dba)₃ (8.8 mg, Acros) andtri(o-tolyl)phosphine] (17.4 mg, Sigma-Aldrich) were added and themixture was heated to 90° C. until the required Mn was reached. Mn wasdetermined by sampling the reaction every hour and analysing by GPC. Atthis point, the pinacolatoboron moieties were substituted by addition ofbromobenzene (1.5 g, Sigma Aldrich) and heating the mixture at 90° C.overnight. The mixture was cooled, poured into MeOH (92.5 mL) and theprecipitate was filtered and dissolved in toluene (100 mL). The solutionwas washed with 1M NaOH (92.5 mL), water (92.5 mL), brine (92.5 mL),dried (magnesium sulphate) and concentrated to give an orange solid. Thesolid was dissolved in toluene (10 mL) and filtered through a silicaplug eluting THF:toluene (50:50). The filtrates were concentrated to anorange solid that was dissolved in THF (10 mL) and added dropwise toMeOH (50 mL). The suspension was stirred for 15 minutes then filtered togive a yellow solid that was dissolved in toluene, treated with charcoal(3×80 mg) and the filtrates were concentrated. The solid was dissolvedin THF (10 mL) and added dropwise to MeOH (50 mL). The resulting solidwas filtered and dried to give the title compound as a yellow solid.Yield: 620 mg. Mn=3900 g/mol. n=13.8. Polydispersity=2.29.

Synthesis of 30:70 4-isopropylcyano-PTAA: 2,4-Dimethyl-PTAA 9

Toluene (170 mL) was degassed for 10 minutes then2-(4-(bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile (2.70 g),N,N-bis(4-bromophenyl)-2,4-dimethylaniline (1.66 g) and2,4-dimethyl-N,N-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline(5.01 g) were added followed by (Ph₃P)₄Pd (27.7 mg, Peakdale Molecular)and 1M Na₂CO₃ (95 mL). The mixture was heated to 95° C. until therequired Mn was reached. Mn was determined by sampling the reaction andanalysing by GPC. At this point, the pinacolatoboron moieties weresubstituted by addition of bromobenzene (7.5 g, Sigma Aldrich) andheating the mixture at 95° C. overnight. The mixture was then cooled andpoured into methanol (1325 mL). The resulting suspension was collectedby filtration, dissolved in toluene (250 mL) and filtered throughcelite. The filtrates were washed with 1M NaOH (250 mL), water (250 mL),brine (250 mL), dried (MgSO₄) and concentrated to give a yellow solid.To remove the bromide moieties, this was dissolved into degassed toluene(170 mL) and to it was added 1M Na₂CO₃ (95 mL), (Ph₃P)₄Pd (27.7 mg,Peakdale Molecular) and phenylboronic acid (5.81 g, Apollo Scientific).This was heated to 95° C. overnight. The workup was repeated as above,concentrating to 150 mL. This was filtered through silica, eluting with50:50 toluene:THF mixture. The filtrates were concentrated to a brownsolid which was dissolved in toluene (100 mL), treated with charcoal(3×500 mg) and the filtrates were concentrated. The solid was dissolvedin THF (50 mL) and precipitated into MeOH (250 mL). The resultingsuspension was filtered to yield the title compound as a grey solid.Yield: 4.0 g. Mn=1992 g/mol. n=7.0. Polydispersity=3.35.

The dielectric constant of polymer 9 was 3.6.

Alternative Method

Toluene (34 mL) was degassed for 10 minutes then2-(4-(bis(4-bromophenyl)amino)phenyl)-2-methylpropanenitrile 4 (537.4mg), N,N-bis(4-bromophenyl)-2,4-dimethylaniline 7 (328.7 mg) and2,4-dimethyl-N,N-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)aniline8 (1.00 g) were added followed by (Ph₃P)₄Pd (5.7 mg, Peakdale Molecular)and 1M Na₂CO₃ (19 mL). The mixture was heated to 95° C. for 12 hoursthen the pinacolatoboron moieties were substituted by addition ofbromobenzene (1.5 g, Sigma Aldrich) and heating the mixture at 95° C.overnight. The bromide moieties were then substituted by addition ofphenylboronic acid (1.16 g, Apollo Scientific) and heating the mixtureovernight. Purification as above gave the product as a grey solid.Yield: 825 mg. Mn=2300 g/mol. n=8.1. Polydispersity=3.1

Comparative Example (10) Polymer (10) 2,4-dimethyl-PTAA polymer

Synthesis of the 2,4-Dimethyl-polytriarylamine polymer (10)

A 1 L three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. 500 mL of anhydrousN,N-dimethylacetamide (Sigma Aldrich) was charged to the vessel using acannula needle, and the solution was degassed with argon for 15 minutes.Triphenylphosphine (19.65 g, Sigma Aldrich), 2,2′-bipyridyl (0.92 g,Sigma Aldrich), zinc (29.65 g, Alfa-Aesar) and nickel (II) chloride(0.51 g, Sigma Aldrich) were added and the reaction mass heated to70-80° C., whereupon the mixture turned red-brown in colour. After 20minutes, a few crystals of iodine were added and the mixture was leftstirring at 70-80° C. for a further 40 minutes. The 2,4-dimethyl PTAAmonomer (49.88 g, see Example 4) was added, followed by anhydroustoluene (75 mL, Aldrich). The reaction was left to stir at 70-80° C. for19 hours. The reaction was cooled to room temperature and filtered. Thesolids were washed with the filtrate before being transferred back intothe vessel and dissolved into toluene (500 mL) at 50° C. The mixture wascooled to room temperature, and the excess zinc was quenched by slowaddition of concentrated hydrochloric acid (80 mL). The layers wereseparated and the organic phase washed with 10% aqueous sodium chloridesolution (3×250 mL). The organic phase was then dried (sodium sulphate)and filtered through a celite pad. The filtrates were concentrated togive a yellow solid. This was dissolved in toluene (200 mL) and filteredthrough a pad of silica gel (100 g), eluting with toluene until nofurther product was seen by UV spot on a TLC plate. The filtrates werecombined and concentrated to give a yellow solid. A solution of thissolid in 150 mL of tetrahydrofuran was prepared and then added into astirred portion of methanol (750 mL) over 1 hour. The suspension wasstirred for 1 hour before being filtered, washed with methanol (2×100mL) and dried to give a yellow powder. Yield: 25.78 g. Mn=3263 g/mol,n=12.0, polydispersity=1.7.

Hydrodechlorination Process

A 1 L autoclave fitted with magnetic stirrer was charged with 11.22 g ofthe 2,4-dimethyl-polytriarylamine polymer and 500 mL of toluene (FisherScientific). To this was added a slurry of 10% palladium on carbon (5.6g, Sigma Aldrich) in water (90 mL). Triethylamine (17 mL, Alfa-Aesar)was added to this stirred solution and the reaction mixture hydrogenatedat 300 psi/50° C. for 72 hours. After cooling and venting, the mixturewas filtered through celite, eluting with toluene. The filtrates werewashed with water (4×500 mL), dried (sodium sulphate) and concentratedto give a yellow solid. This material was dissolved in toluene (100 mL)and filtered through a silica pad, eluting with toluene until no furtherproduct was seen by a UV spot on a TLC plate. The filtrates were thenconcentrated to give a yellow solid. A 500 mL round bottom flask wascharged with a solution of the product in toluene (250 mL) and activatedcharcoal (1.2 g). The mixture was heated to 60° C. for 30 minutes, thenfiltered hot through a Buchner funnel, washing with the minimum amountof toluene. This carbon screening process was repeated twice more,filtering the third treatment through a glass sinter. The filtrates wereconcentrated to give a dark yellow solid. A solution of this material intetrahydrofuran (60 mL) was prepared and added slowly to a stirredportion of methanol (300 mL). The resulting suspension was stirred for 1hour, collected by vacuum filtration, washed with methanol (3×50 mL) anddried to give the product as a pale yellow powder. Yield: 9.75 g.Mn=3138 g/mol. n=11.6. Polydispersity=1.8. Chlorine content=19 ppm.

The permittivity of the 2,4-Dimethyl PTAA polymer (10) was 3.0

Comparative Examples (11)-3-Methoxy-PTAA and (12)-2,4-Difluoro-PTAA

these polymers were synthesised using the same methodology as describedin Examples 1 to 9. The permittivities of the corresponding PTAApolymers are listed in Table 1.

Comparative Example 13 Synthesis of the 3,5-bistrifluoromethylpolytriarylamine polymer (13)

Synthesis of the 3,5-bis(trifluoromethyl) monomer

A 2 L 3-neck round bottom flask fitted with mechanical stirrer,thermometer, condenser and argon inlet was charged with toluene (1.125L), palladium acetate (494.4 mg, Precious Metals) and(±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (1.37 g, Alfa-Aesar)were added to the vessel and the contents were heated to 50° C. and thencooled to room temperature once reached and left to stir for 1 hour.3,5-bis(trifluoromethyl)iodobenzene (75 g, Maybridge),bis(4-chlorophenyl)aniline (52.5 g) and sodium-tert-butoxide (23.28 g,Alfa-Aesar) were added to the vessel which was heated to 110° C. for 8hours. The reaction was cooled and water (750 mL) was added. The mixturewas filtered and the layers separated. The organic phase was washed withwater, filtered through a pad of celite and concentrated. The crudeproduct was purified by chromatography using heptane as an eluent,followed by recrystallising twice from methanol. Yield: 35 g. ¹H NMR(400 MHz, CDCl₃): δ 7.31-7.29 (7H, m, ArH), 7.04-7.02 (3H, m, ArH).

Synthesis of the 3,5-bis(trifluoromethyl) PTAA oligomer (13)

A 1 L three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (250 mL,Sigma-Aldrich) was charged and degassed for 15 minutes.Triphenylphosphine (7.58 g, Sigma-Aldrich), 2,2′-bipyridyl (346.2 mg,Sigma-Aldrich), zinc (11.17 g, Alfa-Aesar) and nickel (II) chloride(216.7 mg, Sigma-Aldrich) were added to the vessel. The contents wereheated to 70-80° C. where the mixture turned red-brown in colour. A fewcrystals of iodine were added, and the reaction was left to stir for 1hour. The 3,5-bis(trifluoromethyl) monomer (24.98 g) was added to thevessel. Anhydrous toluene (41 mL, Sigma-Aldrich) was added and thereaction was left to stir for 19 hours, before being cooled to roomtemperature. The reaction was filtered, washing the solids withN,N-dimethylacetamide (100 mL). The filter cake was dissolved intetrahydrofuran (300 mL), filtered through a celite pad andconcentrated. This material was dissolved into tetrahydrofuran (250 mL)and filtered through silica, eluting with tetrahydrofuran. Productfractions were combined and concentrated to give a yellow solid. Thiswas dissolved in 2-methyltetrahydrofuran (230 mL), washed with 1M sodiumhydroxide solution (200 mL), water (200 mL), 10% sodium chloridesolution (200 mL) and water (200 mL) before being concentrated to give ayellow solid (8.5 g). This was dissolved in tetrahydrofuran (50 mL) andcharcoal treated three times (3×0.85 g of charcoal) then concentrated.This material was dissolved in tetrahydrofuran (60 mL) and addeddropwise to a stirred portion of methanol (300 mL). The resultingsuspension was stirred for 1 hour before being collected by filtrationand dried. Yield: 7.5 g. Mn=5350 g/mol. n=14.1. Polydispersity=1.3.

The dielectric constant of polymer (13) was 2.8.

Comparative Example 14 Polymer (14), 2-Methoxy backbone PTAA homopolymer

Synthesis of the 2-methoxy backbone PTAA monomer (a) Synthesis of4-chloro-2-methoxyaniline

A mixture of 5-chloro-2-nitroanisole (1.0 g, Sigma-Aldrich), ammoniumformate (3.36 g, Alfa-Aesar) and 10% platinum on carbon (100 mg) in MeOH(10 mL) was heated to reflux for 45 minutes then cooled to roomtemperature and filtered through celite, washing with MeOH. Thefiltrates were concentrated and the residue was dissolved in EtOAc andwater. The organics were dried (MgSO₄) and concentrated to a brown oil.The material was absorbed onto silica and columned eluting ethylacetate/heptane mixtures to give the product as a brown oil. Yield: 0.7g. ¹H NMR (400 MHz, CDCl₃): δ 6.72-6.78 (2H, m, ArH), 6.58-6.62 (1H, m,ArH), 3.83 (3H, s, OMe).

(b) Synthesis of 4-chloro-N-(4-chlorophenyl)-2-methoxyaniline

A solution of palladium (II) acetate (949 mg, Precious Metals Online)and (+/−)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (2.63 g,Alfa-Aesar) in toluene (1000 mL) was heated to 50° C. under argon thencooled to room temperature. 4-Chloro-2-methoxyaniline (66.6 g),4-iodochlorobenzene (105.81 g, Apollo Scientific) and sodiumtert-butoxide (44.68 g, Alfa-Aesar) were added and the mixture washeated to reflux for 90 minutes. The mixture was cooled to roomtemperature, quenched with water (500 mL) then the organics wereseparated, dried (MgSO₄) and concentrated. The residue was absorbed ontosilica and columned eluting ethyl acetate/heptane mixtures to give theproduct as a dark orange oil that solidified on standing. Yield: 97.86g. ¹H NMR (400 MHz, CDCl₃): δ 7.18-7.23 (2H, m, ArH), 7.12 (1H, d, ArH),7.00-7.05 (2H, m, ArH), 6.82-6.85 (2H, m, ArH), 6.00 (1H, br s, NH),3.87 (3H, s, OMe).

(c) Synthesis of4-chloro-N-(4-chlorophenyl)-2-methoxy-N-phenylaniline-2-MeO-backbonePTAA monomer

Palladium(II) acetate (3.84 g, Precious Metals Online) and4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (9.91 g, ManchesterOrganics) were dissolved in toluene (690 mL) and stirred at roomtemperature under argon for 1 hour.4-Chloro-N-(4-chlorophenyl)-2-methoxyaniline (45.9 g), iodobenzene (47.9mL, Sigma-Aldrich) and sodium tert-butoxide (42.78 g, Alfa Aesar) wereadded and the mixture was heated to 85° C. overnight. The mixture wascooled to room temperature, quenched with water (690 mL) and filteredthrough celite. The organics were separated, dried (MgSO₄) andconcentrated to a black oil. The material was absorbed onto silica andcolumned eluting ethyl acetate/heptane mixtures to give a brown oil.MeOH was added and the mixture was cooled to 0° C. and stirred for 1hour. The solid was filtered and recrystallised from DCM/MeOH to givethe product as a white solid. Yield: 14.5 g. ¹H NMR (400 MHz, CDCl₃): δ7.18-7.23 (2H, m, ArH), 7.10-7.15 (2H, m, ArH), 7.05 (1H, d, ArH),6.89-6.99 (5H, m, ArH), 6.84-6.88 (2H, m, ArH), 3.63 (3H, s, OMe).

Synthesis of the 2-methoxy backbone PTAA polymer 14

A 500 mL three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (150 mL,Sigma-Aldrich) was charged and degassed for 15 minutes.Triphenylphosphine (5.75 g, Sigma-Aldrich), 2,2′-bipyridyl (263.1 mg,Sigma-Aldrich), zinc (8.48 g, Alfa-Aesar) and nickel (II) chloride(163.8 mg, Sigma-Aldrich) were added to the vessel and the contents wereheated to 70-80° C. where the mixture turned red-brown in colour. A fewcrystals of iodine were added, and the reaction was left to stir for 1hour. The monomer (14.5 g) was added to the vessel followed by anhydroustoluene (24 mL, Sigma-Aldrich) and the mixture was left to stirovernight before being cooled to room temperature. The reaction wasfiltered and the filtrates were added dropwise to MeOH (1150 mL). Thesolids were filtered, washed with MeOH and dried before beingredissolved in toluene (750 mL). The solution was washed with 1Mhydrochloric acid (250 mL), water (250 mL), 10% brine (250 mL), dried(MgSO₄) and concentrated to give a yellow solid. This was dissolved intoluene and passed through a silica pad eluting toluene then 50:50toluene:THF. The filtrates were concentrated then redissolved in tolueneand charcoal treated (3×1.24 g). The filtrates were then concentrated togive a yellow solid. This material was dissolved in THF (250 mL) andadded dropwise to a stirred portion of methanol (1250 mL). The resultingsuspension was stirred for 30 minutes before being collected byfiltration to give a pale yellow powder. Yield: 8.93 g. Mn=3221 g/mol.n=11.8. Polydispersity=2.43.

The dielectric constant of poymer (14) was 3.29

Comparative Example 15 Polymer (15) 4-Phenoxy-PTAA homopolymer

Synthesis of the 4-phenoxy monomer

A 1 liter 3-neck round bottom flask fitted with magnetic stirrer,thermometer, condenser and argon inlet was charged with 300 mL toluene,palladium acetate (250 mg, Precious Metals) and(±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (0.69 grams (g),Alfa-Aesar) were added to the vessel and the contents were heated to 50°C. and then cooled to room temperature once reached and left to stir for1 hour. 4-phenoxyaniline (20.02 g, Alfa-Aesar), 4-chloroiodobenzene(59.96 g, Apollo Scientific) and sodium-tert-butoxide (22.83 g,Alfa-Aesar) were added to the vessel which was heated to 110° C. for 54hours. The reaction was cooled and water (200 ml) was added. The mixturewas filtered and the layers separated. The organic phase washed withwater, filtered through a pad of celite, dried over sodium sulphate andconcentrated. The crude product was purified by automatedchromatography, using 2% ethyl acetate in heptane as an eluent, and thenby silica pad using heptane to remove impurities and then 10% ethylacetate in heptane. Product fractions were combined and concentratedYield: 29 g. ¹H NMR (400 MHz, CDCl₃): δ 7.5-6.9 (17H, m, ArH)

Synthesis of the 4-phenoxy PTAA oligomer

A 500 ml three neck round bottom flask was fitted with overhead stirrer,thermometer, air condenser, Claisen adaptor and septum inlet. Theapparatus was flushed with argon. N,N-dimethylacetamide (130 mL,Aldrich) was charged and degassed for 15 minutes. Triphenylphosphine(1.50 g, Aldrich), 2,2′-bipyridyl (69.8 mg, Aldrich), zinc (2.24 g,Alfa-Aesar) and nickel (II) chloride (42.4 mg, Aldrich) were added tothe vessel. The contents were heated to 70-80° C. where the mixtureturned red-brown in colour. A few crystals of iodine were added, and thereaction was left to stir for 1 hour. The monomer (13 g) was added tothe vessel, followed by anhydrous toluene (45.5 mL, Aldrich). After 3hours, further nickel (II) chloride (42.8 mg) was added and the reactionwas left to stir for 15 hours, before being cooled to room temperature.The reaction was filtered through celite, eluting withN,N-dimethylacetamide (50 mL). Solids began precipitating in thefiltrates which were collected by filtration. The filtrates weremeasured (350 mL) and added dropwise to a stirred portion of methanol(1750 mL). The suspension was stirred for 1 hour, collected by vacuumfiltration and washed with methanol. The solids were combined with thesolids collected from the celite filtration and dissolved intetrahydrofuran (250 mL), washed three times with 10% sodium chloridesolution (200 ml) and concentrated to give a yellow solid. This materialwas dissolved into tetrahydrofuran (250 mL) and filtered through silica,eluting with tetrahydrofuran. Product fractions were combined andconcentrated to give a yellow solid (15 g). This material was dissolvedin tetrahydrofuran (250 mL) and charcoal treated three times (3×1.5 g ofcharcoal). The filtrates were concentrated. This material was dissolvedin tetrahydrofuran (120 mL) and added dropwise to a stirred portion ofmethanol (120 mL). The resulting suspension was stirred for 1 hourbefore being collected by filtration and dried. Yield: 8.6 g. Mn=2047g/mol. n=6.1. Polydispersity=2.1.

The dielectric constant of polymer (15) was 2.7.

The invention claimed is:
 1. A semiconducting polymer having apermittivity greater than 3.4 at 1000 Hz and a charge mobility in thepure state of greater than 10⁻⁷ cm²V⁻¹S⁻¹, wherein thesemiconductingpolymer comprises substituted triarylamine repeat units,and wherein the substituted triarylamine repeat units comprise at leastone of the following attributes: (i) indirectly substituted by at leastone cyano group, wherein the at least one cyano group is attached to anaromatic group of a substituted triarylamine by a linking group; (ii)directly substituted by at least two alkoxy groups, wherein the at leasttwo alkoxy groups are in the 2, 4 or 6 positions of a pendant aromaticring; and combinations thereof.
 2. The semiconducting polymer accordingto claim 1, wherein the triarylamine repeat units comprise at least oneof the following structures:


3. The semiconducting polymer according to claim 1, wherein thesemiconducting polymer is represented by Formula (I) comprising firstmonomer units, second monomer units, and combinations thereof:

wherein each R^(x) is independently selected from the group consistingof hydrogen, an alkyl group, an alkoxy group, halogen, a nitro group,R^(y) , and combinations thereof; wherein each R^(y) is independently anorganic group that includes at least one CN group, with the proviso thatat least one repeat unit in the semiconducting polymer includes an R^(y)group; wherein the sum of indices (j+k+l) is at least one; wherein eachR^(z) is independently an alkyl group optionally substituted by at leastone substituent selected from the group consisting of hydroxyl, alkoxy,alkylsulphonyl, halogen, cyano, nitro, amino, carboxyl, and combinationsthereof; wherein each A is independently selected from the groupconsisting of hydrogen, halogen any suitable end-capping group, andcombinations thereof; wherein j and l are independently in eachoccurrence 0 to 4; wherein k is independently in each occurrence 0 to 5;wherein a is the number of first monomer units; and wherein b is thenumber of second monomer units, which may be
 0. 4. A semiconductingpolymer according to claim 1, wherein the semiconducting polymer isrepresented by Formula (I) comprising first monomer units, secondmonomer units, and combinations thereof:

wherein each R^(x) is independently selected from the group consistingof hydrogen, an alkyl group, an alkoxy group, halogen, a nitro group,R^(y), and combinations thereof; wherein each R^(y) is independentlyselected from the group consisting of a cyano group (CN), an organicgroup that includes at least one CN group, and combinations thereof;wherein the semiconducting polymer comprises at least two alkoxysubstituents R^(x) in the 2, 4 or 6 positions of a pendant aromaticring; wherein the sum of indices (j+k+l) is at least one; wherein eachR^(z) is independently an alkyl group optionally substituted by at leastone substituent selected from the group consisting of hydroxyl, alkoxy,alkylsulphonyl, halogen, cyano, nitro, amino, carboxyl, and combinationsthereof; wherein each A is independently selected from the groupconsisting of hydrogen, halogen, any suitable end-capping group, andcombinations thereof; wherein j and l are independently in eachoccurrence 0 to 4; wherein k is independently in each occurrence 0 to 5;wherein a is the number of first monomer units; and wherein b is thenumber of second monomer units, which may be
 0. 5. The semiconductingpolymer according to claim 4, wherein methoxy groups are substituted inthe 2- and 4-positions on the pendant aromatic ring.
 6. Thesemiconducting polymer according to claim 1, wherein the semiconductingpolymer is a copolymer represented by the following formula:

wherein a is the number of first monomer units, wherein b is the numberof second monomer units, and wherein each A is independently selectedfrom the group consisting of hydrogen, halogen, any suitable end-cappinggroup, and combinations thereof.